Circuit breaker having current transformer with incorporated optical link

ABSTRACT

A circuit breaker comprising a hollow insulating column, and an insulated cut-off chamber supported by the column and having movable and fixed contact members therein that are connected to terminals. An optical link current transformer is also provided and comprises a polarized light beam transmitter arranged at the bottom of the column which transmits a beam to the interior of the column, an optical Faraday element, and a toroidal winding directly securing one of the terminals connected to the contact members. The Faraday element is connected to the toroidal winding so as to be subjected to magnetic fields generated by current in the winding. Reflecting mirrors are provided in the column and in the cut-off chamber for transmitting light beams from the transmitter through the column and cut-off chamber and to the Faraday element. Additional reflecting mirrors are provided to transmit light beams from the Faraday element back through the cut-off chamber, the column and then to a photoelectric cell arranged at the base of the column.

3 g 1 x12 3 9 6%? 9 a??? J O United States l 3,686,567

Orgeret Aug. 22, 1972 CIRCUIT BREAKER HAVING Primary Examiner-Archie R.Borchelt CURRENT TRANSFORMER WITH Assistant g y INCQRPORATED OPIIQALLINK i Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak.

[72] Inventor: Lucien Orgeret, 72 Boulevard Pinel, [57] ABSTRACT 69-Lyon3e, France A t b ak h n ul crrcur re er comprising a o ow rns atmg [22]June 1970 column, and an insulated cut-off chamber-supported 21 AWL 4 ,32 by the column and having movable and fixed contact members thereinthat are connected to terminals. An optical link current transformer isalso provided and Foreign Appliumon Priority Data comprises a polarizedlight beam transmitter arranged June 13, 1969 France ..-...6919726 atthe bottom of the column which transmits a beam to the interior of thecolumn, an optical Faraday ele- 52] us. (:1. ..324/96 250 225 350/150and wmidal Winding directly Sewing 51 Int. Cl. 1 ozf 1/2 6611. 31/00 theterminals connected to the contact members. The [58] Field of Search i250/217 S Faraday element is connected to the toroidal winding 315/159.350/156 so as to be subjected to magnetic fields generated by current inthe winding. Reflecting mirrors are provided in the column and in thecut-off chamber for [56] References Cited transmitting light beams fromthe transmitter through UNITED STATES PATENTS the column and cut-offchamber and to the Faraday element. Additional reflecting mirrors areprovided to 3,324,393 6/1967 Casey et a1. ..324/96 transmit light beamsfrom the Faraday element back 2,081,839 5/1937 Rankin ..324/96 throughthe cutoff chamber, the column and then to a photoelectric cell arrangedat the base of the column.

2 Clains, 6 Drawing Figures Patented Aug. 22, 1972 3 Sheets-Sheet 1atented Aug. 22, 1972 3 Sheets-Sheet 2 FIG3 Patented Aug. 22, 1972 3Sheets-Sheet 5 CIRCUIT BREAKER HAVING CURRENT TRANSFORMER WITHINCORPORATED OPTICAL LWK BACKGROUND OF THE INVENTION This inventionrelates to an electrical circuit breaker involving a current transformerwith incorporated optical link.

The invention applies to a circuit breaker involving a hollow insulatingcolumn supporting at least one chamber in which are arranged cut-ofimembers connected to connection conductors traversing the walls of saidchamber in insulating terminals.

It is known, for example, on the basis of US. Pat. No. 3,324,393, thatone can associate a circuit breaker, thus constituted, with an opticalcurrent transformer involving the following elements:

A polarized light beam emitter, arranged at the bottom of the column,means for transmitting the beam to the interior of the column up to theinput of an optical Faraday element subjected to the magnetic fieldcreated by a coil connected to a toroidal winding in whose axis passesone of the above-mentioned connection conductors, and means forconducting the light beam, coming out of said Faraday element, into thehollow column, up to a photoelectric cell arranged at the base of thecolumn.

However, in such a circuit breaker, the magnetic torus is arrangedaround the output terminal of the connection conductor, which requiresit to have a large diameter, and it is therefore expensive to make andit is subject to heavy losses.

SUMMARY OF THE INVENTION The circuit breaker according to the inventiondiffers from the above-described known circuit breaker by the fact thatthe magnetic torus is arranged directly around the connection,conductor. Instead of beingoutside an insulating enclosure, for example,made of porcelain, it is positioned inside the enclosure.

This enclosure may be an auxiliary chamber attached to the cut-offchamber or it may be made up of the cutoff chamber itself, with theinput and output light beams then running parallel to the contact piecesarranged in the chamber or even inside the contact pieces, if the latterare hollow.

In the case where two cut-off chambers are supported by the sameinsulating column, the circuit breaker according to the invention mayinvolve a single light beam source at the base of the column andreflecting means for sending the beam toward two Faradayelements-magnetic toms assemblies associated respectively, with the twochambers, and to return the output beam of the assemblies towardphotoelectric cells.

Likewise, according to the invention, when the column and/or the cut-offchambers are filled with a relatively opaque liquid, such as oil, tubesfilled with air may be arranged in the column and/or chambers for thepassage of the light beams.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are elevational views,partly in section and with parts broken away;

FIG. 3 is a schematic view showing a first embodiment of this invention;

FIG. 4 is an elevational view, partly in section and with parts brokenaway;

FIG. 5 is a schematic view of a second embodiment of the invention; and

FIG. 6 is an elevational view, partly in section and with parts'brokenaway, of a third embodiment of the invention.

FIG. 1 is apartial cross-section view along axis AB in FIG. 2 and FIG. 2is a partial cross-section view along axis CD in FIG. 1, showing thefirst form of the invention with the auxiliary chamber for thetransmission of light beams.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, andparticularly in FIGS. 1 and 2, FIG. 1 refers to a base enclosuresupporting a hollow insulating column 2, the latter in turn supporting alateral cut-off chamber 3 containing the fixed contact piece 4 and themovable contact piece 5 of the circuit breaker, and the control rodsystem 6 for the movable contact piece.

To the base enclosure 1 there are connected, on the one hand, apolarized light emission device, designated overall by 7, of a type wellknown in the art, and, on the other hand, a light reception device,designated by 8, comprising, in the known manner, a photoelectric cellassociated with an amplifier.

The light emission and reception devices, 7 and 8, respectively, are incommunication with the enclosure 1 by means of transparent fittings 9and 10, respectively.

The incident light beam from the light emission device 7 is sent intothe hollow column 2 by a mirror 11, through a transparent fitting l5,and falls upon a mirror 12 which reflects it into an auxiliary chamber13, parallel to the cut-off chamber 3.

At the end of this chamber 13, the beam is reflected by a mirror 14 inthe input of a Faraday-effect element, as shown in FIG. 3. This devicecomprises, in a known manner, a transparent cylinder 16 made of flintglass, on whose ends are glued, respectively, a polarizer element and ananalyzer element, and it is placed in the magnetic field of a coil 17supplied by a secondary winding of a current transformer 18 in the formsof a toms which, according to the invention, and contrary to the priorart, is arranged directly around a terminal 19, connected to fixedcontact 4 of the circuit breaker.

The light beam, coming out of the Faraday-effect element, is reflected,by mirrors 20, 21 and 22, to the photoelectric cell of the lightreception device 8.

FIGS. 4 and 5 show, schematically, one variant of the application of theoptical-link current transformer with circuit breaker having two cut-offchambers 3 and 3,, carried by a single column 2.

This variant involves a single light beam transmitter, identical to theone in FIG. 1, and which has therefore not been shown here, and anauxiliary enclosure 23 attached to the assembly of the two cut-offchambers.

In this auxiliary enclosure, the incident light beam falls upon asemitransparent mirror 24; a portion of said beam is reflected by thismirror 24, by means of another mirror 25, toward a Faraday-effectdevice, shown schematically at 26, and subjected to the action of acurrent from the terminal 19, coming out of chamber 3. The other portionof the beam, which has traversed the mirror 24, falls upon a mirror 28which reflects it back, by means of another mirror 25,, toward a secondFaraday-effect device 26,, associated with terminal 19 or chamber 3 Thebeams coming out of the two Faraday-efi'ect devices, after reflection bymirrors 29, 29,, fall, respectively, on two mirrors 30, 30,, which sendthem back toward two beam reception devices identical to the receptiondevice 8 according to FIG. 1, and which therefore are not shown in FIGS.4 and 5.

Inanother variant, the light beams are transmitted into the cut-offchamber 3 itself, instead of being transmitted into an auxiliary chamberparallel to the cut-ofl chamber. They are then transmitted parallel tothe contact pieces 4 and 5, either outside them or, if said contactpieces are hollow as shown in FIG. 6, inside the latter.

Finally, it must be noted that, in the case where the column 2 is filledwith a fluid that is opaque, for example, oil, tubes filled with air,such as 31 shown in FIG. 4, may be arranged in said column, one tube forthe outgoing beam and one tube for the return beam.

I claim:

1. In an electrical circuit breaker comprising:

a hollow insulating column,

an insulated cut-off chamber supported at one of its ends by said columnand having movable and fixed contact members therein,

at least one terminal connected to said contact members at the other endof said chamber, an optical link current transformer comprising a lightbeam transmitter, arranged at the bottom of said column,

means for transmitting this beam to the interior of said column,

an optical Faraday element,

a toroidal winding surrounding said terminal,

means for subjecting said Faraday element to a magnetic field, generatedby current in said winding, means for transmitting said light beam tosaid Faraday element, a photoelectric cell arranged at the base of saidcolumn, and means for conducting the light beam coming out of saidFaraday element through said column and to said photoelectric cell; theimprovement wherein said toroidal winding directly surrounds saidterminal, said optical Faraday element is located close to said terminaland said column is filled with a relatively opaque liquid and tubes arearranged in said column for the passage of light beams.

2. In an electrical circuit breaker comprising:

a hollow insulating column,

an insulated cut-ofi chamber supported at one of its a toroidal windinsurroundin said terminal, means for subjec rig said Far day element to amag netic field generated by current in said winding,

means for transmitting said light beam to said Faraday element,

a photoelectric cell arranged at the base of said column, and

means for conducting the light beam coming out of said Faraday elementthrough said column and to said photoelectric cell; the improvementwherein said toroidal winding directly surrounds said terminal, saidoptical Faraday element is located close to said terminal, two cut-offchambers are supported by the insulating column; wherein contactmembers, terminals, a Faraday element and a toroidal winding areassociated with each of said chambers; and wherein a semireflectingmirror is provided for the purpose of reflecting to each chamber thelight beam issuing from said transmitter arranged at the bottom of saidcolumn, and reflecting mirrors are provided for the purpose ofreflecting the output light beams from each of the chambers toward saidphotoelectric cell arranged at the base of said colurrm.

1. In an electrical circuit breaker comprising: a hollow insulatingcolumn, an insulated cut-off chamber supported at one of its ends bysaid column and having movable and fixed contact members therein, atleast one terminal connected to said contact members at the other end ofsaid chamber, an optical link current transformer comprising a lightbeam transmitter, arranged at the bottom of said column, means fortransmitting this beam to the interior of said column, an opticalFaraday element, a toroidal winding surrounding said terminal, means forsubjecting said Faraday element to a magnetic field generated by currentin said winding, means for transmitting said light beam to said Faradayelement, a photoelectric cell arranged at the base of said column, andmeans for conducting the light beam coming out of said Faraday elementthrough said column and to said photoelectric cell; the improvementwherein said toroidal winding directly surrounds said terminal, saidoptical Faraday element is located close to said terminal and saidcolumn is filled with a relatively opaque liquid and tubes are arrangedin said column for the passage of light beams.
 2. In an electricalcircuit breaker comprising: a hollow insulating column, an insulatedcut-off chamber supported at one of its ends by said column and havingmovable and fixed contact members therein, at least one terminalconnected to said contact members at the other end of said chamber, anoptical link current transformer comprising a light beam transmitter,arranged at the bottom of said column, means for transmitting this beamto the interior of said column, an optical Faraday element, a toroidalwinding surrounding said terminal, means for subjecting said Faradayelement to a magnetic field generated by current in said winding, meansfor transmitting said light beam to said Faraday element, aphotoelectric cell arranged at the base of said column, and means forconducting the light beam coming out of said Faraday element throughsaid column and to said photoelectric cell; the improvement wherein saidtoroidal winding directly surrounds said terminal, said optical Faradayelement is located close to said terminal, two cut-off chambers aresupported by the insulating column; wherein contact members, terminals,a Faraday element and a toroidal winding are associated with each ofsaid chambers; and wherein a semireflecting mirror is provided for thepurpose of reflecting to each chamber the light beam issuing from saidtransmitter arranged at the bottom of said column, and reflectingmirrors are provided for the purpose of reflecting the output lightbeams from each of the chambers toward said photoelectric cell arrangedat the base of said column.